THE LAMPREYS 5 



3 feet and a weight of over 5 Ibs., its usual 

 size being from 20 to 30 inches ; one of 20 inches 

 is figured (PI. I, Fig. i). It is found in the North 

 Atlantic and Mediterranean, entering rivers in 

 Europe and North America. It is generally dis- 

 tributed in the British Isles, and appears to enter 

 our southern rivers at an earlier date than those in 

 the north, for in the Severn at Worcester the 

 fishing season used to be from February to May, and 

 the spawning was over in June, whereas in Scotland 

 the Lampreys are said not to ascend until June, 

 spawning in July or August. 



By far the best accounts of the life-history of this 

 species have been given by two American authors, 

 Professors S. H. Gage and H. A. Surface, who have 

 studied it in the lakes of the State of New York. 

 Although structurally similar to the true Sea 

 Lamprey, the Lampreys of this region are peculiar 

 in that they never go down to the sea ; they spawn 

 in June, leaving the lakes and seeking out the clear 

 brooks, often stealing a ride by fastening on to large 

 fishes bound in the same direction ; at this time the 

 ground-colour changes from grey to bright yellow, 

 and the two sexes become markedly different in 

 appearance, the male developing a ridge along the 

 middle of the back and a prominent anal papilla, and 

 the female a so-called anal fin. 



The Lampreys migrate independently, and a large 

 majority of the earliest to enter the streams are 

 males; the spawning-place is chosen where the 

 stream is fairly rapid, usually just above a ripple, 

 and where the bottom is sandy but strewn with 

 pebbles. Here a space is cleared by moving the 

 stones a little way down stream until a sandy * nest ' 



